Archive for July, 2015

Descripción clínica y epidemiológica de un brote nosocomial por KPC en Buenos Aires, Argentina

Enf Inf & Microbiol Clínica 2012 V.30 N.7 P.376-79

Ezequiel Córdova a, María Inés Lespada a, Nora Gómez b, Fernando Pasterán c, Viviana Oviedo a y Claudia Rodríguez-Ismael a

a Grupo de Trabajo en Infectología, Hospital General de Agudos «Dr. Cosme Argerich», Buenos Aires, Argentina

b Laboratorio de Microbiología, Hospital General de Agudos «Dr. Cosme Argerich», Buenos Aires, Argentina c Servicio de Antimicrobianos, Departamento Bacteriología, Instituto Nacional de Enfermedades Infecciosas (INEI)-ANLIS «Dr. Carlos G. Malbrán», Buenos Aires, Argentina

Introducción

Klebsiella pneumoniae (K. pneumoniae) productora de carbapenemasa tipo KPC (Kpn-KPC) representa un patógeno emergente, con elevada capacidad de diseminación nosocomial. El objetivo del presente estudio es describir las características clinico epidemiológicas de un brote nosocomial por KpnKPC en Buenos Aires, Argentina.

Métodos

Estudio descriptivo y prospectivo. Se registraron los aspectos clinico epidemiológicos de pacientes con infección por Kpn-KPC (agosto de 2009 a julio de 2010). Se determinó la sensibilidad a los antimicrobianos mediante antibiograma por disco-difusión y por método automatizado (Vitek® 2 CbioMerieux). La búsqueda de carbapenemasa tipo KPC se realizó con la prueba de inhibición con 3-aminofenil-borónico (APB) y se confirmó su presencia por reacción en cadena de la polimerasa (PCR, por sus siglas en inglés). Se realizó tipificación molecular de las cepas aisladas por electroforesis en campo pulsado (PFGE, por sus siglas en inglés).

Resultados

Se registraron 27 casos de infección por Kpn-KPC (sala de cirugía general: n = 8; clínica médica: n = 6; unidad de cuidados intensivos: n = 5; sala de emergencia: n = 4; otras: n = 4). Todos los aislamientos de Kpn-KPC pertenecieron a un mismo clon (ST258). Los sitios de infección fueron: tracto urinario (63%), tracto respiratorio (15%), abdomen (15%), sangre (7%) y hueso (4%). Todos los aislamientos de KPn-KPC fueron solamente sensibles a tigeciclina y colistina. Tratamiento empírico inadecuado: 63%. Tratamiento efectivo dirigido: colistina (74%), tigeciclina (4%), tigeciclina + colistina (22%). Mortalidad global: 59% (atribuible: 26%). Cultivos de vigilancia (hisopados) positivos: 7/70 (10%).

Conclusiones

Se describe la emergencia de un brote nosocomial de Kpn-KPC en Buenos Aires, con alta capacidad de diseminación y elevada mortalidad. La implementación de medidas de control de infecciones es fundamental para reducir la transmisión nosocomial de Kpn-KPC

PDF

http://antimicrobianos.com.ar/ATB/wp-content/uploads/2012/11/Descripci%C3%B3n-cl%C3%ADnica-y-epidemiol%C3%B3gica-de-un-brote-nosocomial.pdf

 

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July 25, 2015 at 3:58 pm

Evaluation of white cell count and differential in synovial fluid for diagnosing infections after total hip or knee arthroplasty.

PLoS One. 2014 Jan 8;9(1):e84751.

Qu X, Zhai Z, Liu X, Li H, Wu C, Li Y, Li H, Zhu Z, Qin A, Dai K.

Author information

Department of Orthopedics, Shanghai Key Laboratory of Orthopedic Implant, Shanghai Ninth People’s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.

Abstract

BACKGROUND:

The accuracy of synovial fluid (SF) white cell count (WCC) and polymorphonuclear (PMN) cell evaluation for predicting prosthetic joint infection (PJI) at the total hip arthroplasty (THA) or total knee arthroplasty (TKA) site is unknown. Therefore, we performed a meta-analysis to summarize the diagnostic validity of SF-WCC and SF-PMN for diagnosing PJI.

METHODS:

The MEDLINE, EMBASE, and OVID databases were searched for studies that had evaluated the diagnostic validity of SF-WCC and SF-PMN between January 1990 and May 2013. Meta-analysis methods were used to pool sensitivity, specificity, diagnostic odd ratios (DORs), the area under the receiver-operating characteristic curve (AUC), positive likelihood ratios (PLR), negative likelihood ratios (NLR), and post-test probability. We also conducted heterogeneity, publication bias, subgroup, and meta-regression analyses.

RESULTS:

Fifteen articles (15 SF-WCC and 14 SF-PMN) that included a total of 2787 patients fulfilled the inclusion criteria and were considered for analysis. The pooled sensitivity and specificity for PJI detection was 0.88 (95% confidence intervals [CI], 0.81-0.93) and 0.93 (95% CI, 0.88-0.96) for SF-WCC and 0.90 (95% CI, 0.84-0.93) and 0.88 (95% CI, 0.83-0.92) for SF-PMN, respectively. The AUC was 0.96 for SF-WCC and 0.95 for SF-PMN. PLR and NLR were 13.3 and 0.13 for SF-WCC, and 7.6 and 0.12 for SF-PMN, respectively. There was no evidence of publication bias. Low-clinical-scenario (pre-test probability, 20%) post-test probabilities were 3% for both negative SF-WCC and SF-PMN results. The subgroup analyses indicated that the sensitivity/specificity of THA were 0.73/0.96 for SF-WCC and 0.85/0.83 for SF-PMN, whereas those of TKA were 0.90/0.91 for SF-WCC and 0.90/0.88 for SF-PMN. We also found that collection of SF-WCC preoperatively had a higher sensitivity than that obtained intraoperatively (0.91 vs. 0.77).

CONCLUSIONS:

SF-WCC and SF-PMN have an adequate and clinically acceptable diagnostic value for detecting PJI, particularly after TKA.

PDF

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3885622/pdf/pone.0084751.pdf

July 25, 2015 at 10:54 am

Efficacy of a novel PCR- and microarray-based method in diagnosis of a prosthetic joint infection.

Acta Orthop. 2014 Apr;85(2):165-70.

Metso L1, Mäki M, Tissari P, Remes V, Piiparinen P, Kirveskari J, Tarkka E, Anttila VJ, Vaara M, Huotari K.

Author information

1Department of Orthopedics , Peijas Hospital, Helsinki University Central Hospital.

Abstract

BACKGROUND AND PURPOSE:

Polymerase chain reaction (PCR) methods enable detection and species identification of many pathogens. We assessed the efficacy of a new PCR and microarray-based platform for detection of bacteria in prosthetic joint infections (PJIs).

METHODS:

This prospective study involved 61 suspected PJIs in hip and knee prostheses and 20 negative controls. 142 samples were analyzed by Prove-it Bone and Joint assay. The laboratory staff conducting the Prove-it analysis were not aware of the results of microbiological culture and clinical findings. The results of the analysis were compared with diagnosis of PJIs defined according to the Musculoskeletal Infection Society (MSIS) criteria and with the results of microbiological culture.

RESULTS:

38 of 61 suspected PJIs met the definition of PJI according to the MSIS criteria. Of the 38 patients, the PCR detected bacteria in 31 whereas bacterial culture was positive in 28 patients. 15 of the PJI patients were undergoing antimicrobial treatment as the samples for analysis were obtained. When antimicrobial treatment had lasted 4 days or more, PCR detected bacteria in 6 of the 9 patients, but positive cultures were noted in only 2 of the 9 patients. All PCR results for the controls were negative. Of the 61 suspected PJIs, there were false-positive PCR results in 6 cases.

INTERPRETATION:

The Prove-it assay was helpful in PJI diagnostics during ongoing antimicrobial treatment. Without preceding treatment with antimicrobials, PCR and microarray-based assay did not appear to give any additional information over culture.

PDF

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3967259/pdf/ORT-85-165.pdf

July 25, 2015 at 10:52 am

Sensitivities, specificities, and predictive values of microbiological culture techniques for the diagnosis of prosthetic joint infection.

Biomed Res Int. 2014;2014:180416.

Jordan RW1, Smith NA2, Saithna A1, Sprowson AP2, Foguet P1.

Author information

1University Hospital Coventry & Warwickshire, Clifford Bridge Road, Coventry CV2 2DX, UK.

2University of Warwick, Coventry CV4 7AL, UK.

Abstract

BACKGROUND:

Identifying the microorganism in a prosthetic joint infection is the key to appropriately targeting antimicrobial treatment. Despite the availability of various techniques, no single test is considered the definitive gold standard.

AIM:

Our aim was to determine the sensitivity, specificity, and positive/negative predictive values for a variety of culture techniques.

METHODS:

We performed a retrospective case series of 219 patients undergoing revision surgery of their hip or knee replacement between May 2004 and February 2013. The patients were classified as either infected or noninfected according to criteria set out by the Musculoskeletal Infection Society. The number and type of samples taken intraoperatively varied between cases but included tissue samples and fluid sent in either blood culture vials or sterile containers.

RESULTS:

The highest sensitivity was found with blood culture vials (0.85) compared to fluid in sterile containers (0.26) and tissues samples (0.32). Blood culture vials also had a better specificity and positive and negative predictive values profile.

CONCLUSION:

We conclude that, of the techniques studied, fluid in blood culture vials had the best profile for the correct identification of microorganisms and advocate its use.

PDF

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4055545/pdf/BMRI2014-180416.pdf

July 25, 2015 at 10:50 am

The value of synovial biopsy, joint aspiration and C-reactive protein in the diagnosis of late peri-prosthetic infection of total knee replacements.

J Bone Joint Surg Br. 2008 Jul;90(7):874-8.

Fink B1, Makowiak C, Fuerst M, Berger I, Schäfer P, Frommelt L.

Author information

1Department of Joint Replacement, General and Rheumatic Orthopaedics, Orthopaedic Clinic, Markgröningen, Kurt-Lindemann-Weg 10, 71706 Markgröningen, Germany. b.fink@okm.de

Abstract

We analysed the serum C-reactive protein level, synovial fluid obtained by joint aspiration and five synovial biopsies from 145 knee replacements prior to revision to assess the value of these parameters in diagnosing late peri-prosthetic infection.

Five further synovial biopsies were used for histological analysis. Samples were also obtained during the revision and incubated and analysed in an identical manner for 14 days. A total of 40 total knee replacements were found to be infected (prevalence 27.6%).

The aspiration technique had a sensitivity of 72.5% (95% confidence interval (CI) 58.7 to 86.3), a specificity of 95.2% (95% CI 91.2 to 99.2), a positive predictive value of 85.3% (95% CI 73.4 to 100), a negative predictive value of 90.1% (95% CI 84.5 to 95.7) and an accuracy of 89%.

The biopsy technique had a sensitivity of 100%, a specificity of 98.1% (95% CI 95.5 to 100), a positive predictive value of 95.2% (95% CI 88.8 to 100), a negative predictive value of 100% and an accuracy of 98.6%.

C-reactive protein with a cut-off-point of 13.5 mg/l had a sensitivity of 72.5% (95% CI 58.7 to 86.3), a specificity of 80.9% (95% CI 73.4 to 88.4), a positive predictive value of 59.2% (95% CI 45.4 to 73.0), a negative predictive value of 88.5% (95% 81.0 to 96.0 CI) and an accuracy of 78.1%.

We found that biopsy was superior to joint aspiration and C-reactive protein in the diagnosis of late peri-prosthetic infection of total knee replacements.

PDF

http://www.bjj.boneandjoint.org.uk/content/90-B/7/874.full.pdf+html

July 25, 2015 at 10:49 am

Prosthetic joint infection diagnosis using broad-range PCR of biofilms dislodged from knee and hip arthroplasty surfaces using sonication.

J Clin Microbiol. 2012 Nov;50(11):3501-8.

Gomez E1, Cazanave C, Cunningham SA, Greenwood-Quaintance KE, Steckelberg JM, Uhl JR, Hanssen AD, Karau MJ, Schmidt SM, Osmon DR, Berbari EF, Mandrekar J, Patel R.

Author information

1Division of Infectious Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA.

Abstract

Periprosthetic tissue and/or synovial fluid PCR has been previously studied for prosthetic joint infection (PJI) diagnosis; however, few studies have assessed the utility of PCR on biofilms dislodged from the surface of explanted arthroplasties using vortexing and sonication (i.e., sonicate fluid PCR).

We compared sonicate fluid 16S rRNA gene real-time PCR and sequencing to culture of synovial fluid, tissue, and sonicate fluid for the microbiologic diagnosis of PJI.

PCR sequences generating mixed chromatograms were decatenated using RipSeq Mixed. We studied sonicate fluids from 135 and 231 subjects with PJI and aseptic failure, respectively. Synovial fluid, tissue, and sonicate fluid culture and sonicate fluid PCR had similar sensitivities (64.7, 70.4, 72.6, and 70.4%, respectively; P > 0.05) and specificities (96.9, 98.7, 98.3, and 97.8%, respectively; P > 0.05). Combining sonicate fluid culture and PCR, the sensitivity was higher (78.5%, P < 0.05) than those of individual tests, with similar specificity (97.0%).

Thirteen subjects had positive sonicate fluid culture but negative PCR, and 11 had negative sonicate fluid culture but positive PCR (among which 7 had prior use of antimicrobials). Broad-range PCR and culture of sonicate fluid have equivalent performance for PJI diagnosis.

PDF

http://jcm.asm.org/content/50/11/3501.full.pdf+html

July 25, 2015 at 10:47 am

Circulating cytokines after hip and knee arthroplasty: a preliminary study.

Clin Orthop Relat Res. 2009 Apr;467(4):946-51.

Shah K1, Mohammed A, Patil S, McFadyen A, Meek RM.

Author information

1Department of Trauma & Orthopaedics, Southern General Hospital, Glasgow, UK. bonecutter@doctors.org.uk

Abstract

Several studies show cytokine concentrations in the peripheral blood are associated with inflammatory activity and surgical trauma.

Cytokine concentrations have more rapid increase and quicker return to normal values than either C-reactive protein or erythrocyte sedimentation rate – a matter of hours rather than weeks; some studies suggest they are better predictors of postoperative infection than C-reactive protein and erythrocyte sedimentation rate.

Threshold levels of interleukin-6 after joint arthroplasty have been determined, but levels of other potentially useful cytokines (tumor necrosis factor-alpha, interleukin-8, interleukin-10, etc) are not known.

We measured the serum levels of 25 different cytokines before and after hip and knee arthroplasties and identified those associated with surgical trauma. Peripheral venous blood samples (one preoperative and three postoperative) from 49 patients undergoing hip or knee arthroplasty were analyzed by laser chromatography.

Three of the 25 cytokines had a relationship with postsurgical trauma, which included one deep infection.

Serum levels of these three cytokines might be useful to identify periprosthetic infections during the early postoperative period when C-reactive protein and erythrocyte sedimentation rate remain elevated.

PDF

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2650047/pdf/11999_2008_Article_562.pdf

July 25, 2015 at 10:42 am

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